1. Field of the Invention
The present invention relates to a tool changing device of a machine tool.
2. Description of the Related Art
In a machine tool, in order to improve forming accuracy and extend the lifetime of a tool, a coolant liquid is supplied to a cutting point of a workpiece being cut by the tool. Moreover, in order to prevent cuttings or chips of the workpiece from scattering, the cutting point may be covered by coolant sprayed as a curtain.
In such a machine tool, the chips may be scattered with the coolant and may adhere, with the coolant, to some parts of the machine tool during processing. If the chips adhere to a tapered portion of the tool, it may be difficult to exchange the tool with another tool, and the forming accuracy may deteriorate after the tool is changed.
Therefore, Japanese Patent Publication (Kokai) No. 2002-273640 discloses a cleaning device, for a machine tool, which can remove chips adhered to a tapered portion of a tool by jetting a coolant liquid during changing the tool.
Also, Japanese Patent Publication (Kokai) No. 8-174372 discloses a chip removing device having a vibrator for vibrating a chip cover, in order to remove chips deposited on a chip cover arranged to prevent the chips or a dust adhering to a sliding surface of a machine tool and/or a shaft drive member.
The proposed devices for removing the chips have a problem that a coolant supplying unit or a mechanism such as a vibrator for removing the chips must be installed, additionally, on the machine tool.
Also, in the above Japanese Patent Publication (Kokai) No. 2002-273640, it is proposed that an air mixing means for mixing an air flow with a coolant liquid should be used, in order to resolve a problem that, when the viscosity of the coolant is relatively high, the jet force of the coolant is reduced and is not sufficient for cleaning the tapered portion of the tool. Therefore, the air mixing means must be newly installed, as well as the coolant supplying unit, in order to remove the chips adhered to the tapered portion of the tool.
On the other hand, the device disclosed in the above Japanese Patent Publication (Kokai) No. 8-174372 can remove the chips or the dust deposited on the chip cover by the vibrator positioned on the opposite side of the chip cover in relation to a cutting area. Therefore, the device cannot remove the chips adhered to the tapered portion of the tool.